Ship embodying very French emphasis (6)
I believe the answer is:
stress
'emphasis' is the definition.
(I know that emphasis can be written as stress)
'ship embodying very french' is the wordplay.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'embodying' is an insertion indicator (to embody can mean to contain or include).
'very french' becomes 'tres' ('very' in French).
'ss' placed around 'tres' is 'STRESS'.
(Other definitions for stress that I've seen before include "'Worry, pressure (6)'" , "Particular emphasis" , "Force" , "result of being overworked" , "suffering" .)